Preparation and ex-vivo ocular delivery of Thermo-responsible pluronic F- 127 hydrogel containing propranolol hydrochloride- loaded Liposomes

Abstract

Objective(s): Poor bioavailability of ophthalmic drops is mainly due to rapid nasolacrimal drainage and eye impermeability of corneal epithelium. The main aim of this study is to prepare a liposomal hydrogel for the ocular delivery of propranolol hydrochloride as a β-blocker drug to enhance drug concentration at the desired site of action.Materials and Methods: In this study liposome formulations were designed and prepared by homogenization and thin-layer methods and then dispersed into the pluronic based hydrogel. The optimized liposomes and liposomal hydrogel were used in Ex-vivo ocular permeation studies through the rabbit’s eye.Results: liposomes showed 170-380 nm particle size, 34-65% entrapment efficiency, and sustained release profiles that 30-60 % of loaded drug released after 24 h. liposomes dispersed in hydrogels demonstrated a lower release rate. Liposomes and liposomal hydrogel increased ocular bioavailability of more than 3-folds. Conclusion: In this study, the administration of thermo-responsible factors (pluronic) led to longer resistance time of the dosage form in the eye because the drug would turn into gel structures at the body temperature. Therefore, a system consisting of both pluronic factor and liposomes will be of great interest because it will pair up the Thermo gelling properties of the pluronic factor and the carrier characteristics of the liposome formulations.